Petra Diamonds Ltd forecast lower-than-estimated production for 2019 after reporting 2018 output at the bottom end of its previously guided range, sending its shares down more than 8 percent on Monday.

Shareholders in mining company Petra Diamonds on Wednesday approved a rights issue to raise about $170 million (127.4 million pounds) to help cut its debt burden, driving the share price around 5 percent higher.

Mining firm Petra Diamonds said on Thursday it would raise $178 million (£133 million) from investors to cut debt after it was hobbled by a strong South African rand, delays in production, strikes and confiscation.

Petra Diamonds Ltd said on Monday it expects full-year core earnings to come in about 10 percent to 15 percent below consensus and cut its 2018 production forecast, sending its shares down 15 percent in early trading.

London-listed Petra Diamonds Ltd said on Wednesday it had received authorisation from the Tanzanian government to resume diamond exports and sales from the Williamson mine, lifting its shares from two-year lows.